Interaction between high-fat diet and ethanol intake leads to changes on the fecal microbiome.

It is known that high-fat diet and alcohol intake can modulate the gut microbiota and consequently affect physiological processes such as fat storage and conditional behavior. However, the effects of the interaction between high-fat diet, its withdrawal and ethanol intake in gut microbiota remain unclear. To address this question, we used an animal model in which C57BL/6 mice were fed on standard (AIN93G) or high-sugar and -butter (HSB) diet for 8 weeks. Then, a protocol of free choice between water and a 10% alcohol solution was introduced, and the HSB diet was replaced with AIN93G in two experimental groups. This model allowed us to distinguish the individual effects of HSB diet and ethanol, and the effects of its interaction on the microbiome. The interaction of those factors was the main driver in the structure changes of the fecal microbial community. HSB diet and ethanol consumption directly affected the abundance of Firmicutes and Actinobacteria phylum, and Clostridiaceae and Coriobacteriaceae family. On the other hand, we also showed that abundance of Bacteroidales_S24-7 family and the Firmicutes/Bacteroidetes ratio were affected only by HSB diet consumption and that ethanol consumption was uniquely responsible for the bacterial translocation to the liver, indicating a breaking of the gut barrier. Finally, we also pointed out that the withdrawal of the HSB diet affects the preference for alcohol and shows a structural resilience in the fecal microbiome. These results highlight the importance of the gut microbiome modulation and its possible role on the phenotype developed by animals.

Bacterial community structure within an activated sludge reactor added with phenolic compounds.

Biodegradation of phenolic compounds in bioreactors is well documented, but the changes in the bacterial populations dynamics during degradation were not that often. A glass bubble column used as reactor was inoculated with activated sludge, spiked with 2-chlorophenol, phenol and m-cresol after 28 days and maintained for an additional 56 days, while the 16S rRNA gene from metagenomic DNA was monitored. Proteobacteria (68.1%) dominated the inoculum, but the bacterial composition changed rapidly. The relative abundance of Bacteroidetes and Firmicutes decreased from 4.8 and 9.4 to <0.1 and 0.2% respectively, while that of Actinobacteria and TM7 increased from 4.8 and 2.0 to 19.2 and 16.1% respectively. Phenol application increased the relative abundance of Proteobacteria to 94.2% (mostly Brevundimonas 17.6%), while that of Bacteroidetes remained low (1.2%) until day 42. It then increased to 47.3% (mostly Leadbetterella 46.9%) at day 84. It was found that addition of phenolic compounds did not affect the relative abundance of the Alphaproteobacteria initially, but it decreased slowly while that of the Bacteroidetes increased towards the end.

Impact of Chestnut and Quebracho Tannins on Rumen Microbiota of Bovines.

The use of phytogenic dietary additives is being evaluated as a means to improve animal productivity. The effect of tannins seems to be the influence not only directly on the digestive process through binding of dietary proteins but also indirectly over their effects on gastrointestinal microbiota. High-throughput sequencing of 16S rRNA gene was used to analyze the impact of dietary supplementation with a blend of chestnut and quebracho tannins on the rumen microbiota of Holstein steers. Bacterial richness was lower in tannins treated animals, while the overall population structure of rumen microbiota was not significantly disturbed by tannins. The ratio of the phyla Firmicutes and Bacteroidetes, a parameter associated with energy harvesting function, was increased in tannins supplemented animals, essentially due to the selective growth of Ruminococcaceae over members of genus Prevotella. Fibrolytic, amylolytic, and ureolytic bacterial communities in the rumen were altered by tannins, while methanogenic archaea were reduced. Furthermore, ruminal pH was significantly higher in animals supplemented with tannins than in the control group, while urease activity exhibited the opposite pattern. Further work is necessary to assess the relation between tannins impact on rumen microbiota and alteration of rumen fermentation parameters associated with bovine performance.

Changes in the Bacterial Community Structure of Remediated Anthracene-Contaminated Soils.

Mixing soil or adding earthworms (Eisenia fetida (Savigny, 1826)) accelerated the removal of anthracene, a polycyclic aromatic hydrocarbon, from a pasture and an arable soil, while a non-ionic surfactant (Surfynol® 485) inhibited the removal of the contaminant compared to the untreated soil. It was unclear if the treatments affected the soil bacterial community and consequently the removal of anthracene. Therefore, the bacterial community structure was monitored by means of 454 pyrosequencing of the 16S rRNA gene in the pasture and arable soil mixed weekly, amended with Surfynol® 485, E. fetida or organic material that served as food for the earthworms for 56 days. In both soils, the removal of anthracene was in the order: mixing soil weekly (100%) > earthworms applied (92%) > organic material applied (77%) > untreated soil (57%) > surfactant applied (34%) after 56 days. There was no clear link between removal of anthracene from soil and changes in the bacterial community structure. On the one hand, application of earthworms removed most of the contaminant from the arable soil and had a strong effect on the bacterial community structure, i.e. a decrease in the relative abundance of the Acidobacteria, Chloroflexi and Gemmatimonadetes, and an increase in that of the Proteobacteria compared to the unamended soil. Mixing the soil weekly removed all anthracene from the arable soil, but had little or no effect on the bacterial community structure. On the other hand, application of the surfactant inhibited the removal of anthracene from the arable soil compared to the untreated soil, but had a strong effect on the bacterial community structure, i.e. a decrease in the relative abundance of Cytophagia (Bacteroidetes), Chloroflexi, Gemmatimonadetes and Planctomycetes and an increase in that of the Flavobacteria (Bacteroidetes) and Proteobacteria. Additionally, the removal of anthracene was similar in the different treatments of both the arable and pasture soil, but the effect of application of carrot residue, earthworms or the surfactant on the bacterial community structure was more accentuated in the arable soil than in the pasture soil. It was found that removal of anthracene was not linked to changes in the bacterial community structure.

Oral supplementation with L-glutamine alters gut microbiota of obese and overweight adults: A pilot study.

OBJECTIVE: The aim of this study was to determine whether oral supplementation with L-glutamine (GLN) modifies the gut microbiota composition in overweight and obese adults. METHODS: Thirty-three overweight and obese adults, ages between 23 and 59 y and body mass index between 25.03 and 47.12 kg/m(2), were randomly assigned to receive either oral supplementation with 30 g of L-alanine (ALA group control) or 30 g of GLN (GLN group) daily for 14 d. We analyzed the gut microbiota composition with new-generation sequencing techniques and bioinformatics analysis. RESULTS: After 14 d of supplementation, adults in the GLN group exhibited statistically significant differences in the Firmicutes and Actinobacteria phyla compared with those in the ALA group. The ratio of Firmicutes to Bacteroidetes, a good biomarker for obesity, decreased in the GLN group from 0.85 to 0.57, whereas it increased from 0.91 to 1.12 in the ALA group. At the genus level, Dialister, Dorea, Pseudobutyrivibrio, and Veillonella, belonging to the Firmicutes phylum, had statistically significant reduction. CONCLUSION: Oral supplementation with GLN, for a short time, altered the composition of the gut microbiota in overweight and obese humans reducing the Firmicutes to Bacteroidetes ratio, which resembled weight loss programs already seen in the literature.

Effect of dietary Bacillus subtilis on proportion of Bacteroidetes and Firmicutes in swine intestine and lipid metabolism.

The ratio of Bacteroidetes and Firmicutes bacterial groups in the gut can affect the ability to absorb nutrients. We investigated the effect of probiotic Bacillus subtilis supplementation of diets on growth performance, fat deposition, blood lipids, copy numbers, and percentage of Bacteroidetes and Firmicutes in cecal contents, as well as mRNA expression of key lipid metabolism enzymes in the liver and adipose tissue of finishing pigs. Twenty-four Duroc x Meishan crossbreed 8-week-old pigs (10.28 ± 0.59 kg) were randomly allocated to two dietary treatments: maize-soybean meal-based diets with B. subtilis (probiotic group) and without B. subtilis (control group). The probiotic diet led to a significant increase in the average daily gain and feed conversion ratio of pigs weighing 10 to 110 kg. The mean backfat depth was increased while leaf lard weights were decreased by probiotic supplementation. Ingestion of probiotics decreased the serum triglyceride and glucose concentrations, but did not change the levels of total cholesterol and free fatty acids in the serum. The mRNA expressions of fatty acid synthase (FAS) and acetyl-CoA carboxylase α (ACCα) in the liver were down-regulated by the dietary probiotic supplement. Conversely, the gene expressions of FAS and ACCα in the adipose tissue increased. The probiotic diet decreased the copy numbers and percentage of Bacteroidetes, while it increased the percentage of Firmicutes in the cecal contents. We conclude that the addition of B. subtilis improves growth performance and up-regulates lipid metabolism in subcutaneous fat of finishing pigs. We conclude that B. subtilis affects lipid metabolism through regulation of the proportion of Bacteroidetes and Firmicutes in the gut.

In vivo antimicrobial effects of endodontic treatment procedures as assessed by molecular microbiologic techniques.

INTRODUCTION: This culture-independent molecular microbiology study evaluated the antimicrobial effects of chemomechanical preparation supplemented by intracanal medication during treatment of teeth with apical periodontitis. METHODS: Samples were taken from 24 necrotic root canals at the baseline (S1), after chemomechanical preparation by using 2.5% NaOCl as the irrigant (S2), and after a 7-day interappointment medication with calcium hydroxide paste in either glycerin (CHG) or camphorated paramonochlorophenol/glycerin (CHPG) (S3). Bacterial, archaeal, and fungal presence was evaluated by polymerase chain reaction (PCR), and bacterial identifications were performed by a closed-ended reverse-capture checkerboard approach targeting 28 candidate endodontic pathogens. RESULTS: All S1 samples were positive for bacteria but negative for both archaea and fungi. Treatment procedures were highly effective in reducing the bacterial levels and number of taxa. Overall, 46% of S2 samples and 62.5% of S3 samples were PCR-negative for bacteria. Specifically, S2 and S3 samples yielded negative PCR results in 50% and 58% of the canals in the CHG group and in 42% and 67% of the canals in the CHPG group, respectively. Except for comparisons with S1 samples, no other statistically significant differences were observed for intragroup and intergroup comparisons involving S2 and S3. Several taxa were still found in S2 and S3 samples, and the most prevalent were Propionibacterium acnes and Streptococcus species. CONCLUSIONS: Bacterial levels and number of taxa were substantially reduced after chemomechanical preparation and intracanal medication. However, presence of detectable levels of persisting bacteria in many cases indicates that the search for more effective antimicrobial treatment strategies should be stimulated.